Crystalline polymerized alpha-monoolefinic hydrocarbons containing an organic addition polymer and a metal compound to improve their dyeability



United States Patent 3,240,552 (IRYSTALLENE PULYMERIZED a-MONQOLEFINIC HYDRGCAREQNS (IUNTAENENG AN @RGANHC ADDHIGN PULYMER AND A METAL coas- PQUND T0 HMPRQVE THEL'R DYEAEELKTY Frederick E. Joyner, John R. tlaldweii, and Russell Gillrey, Kingsport, Tenn, assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed May 15, 196i, er. No. 109,828 14 (Ilaims. (Ci. 839) This invention relates to the production of dyeable polypropylene fibers. More particularly, this invention relates to crystalline type polypropylene fibers having excellent dye aflinity and fastness properties as well as improved fastness to dry cleaning solvents such as perchloroethylene. In a more specific aspect, this invention relates to polypropylene fibers which contain a metal salt and are modi fied with certain addition type polymeric modifiers.

It is known that polypropylene, particularly the polypropylene which is partially or completely crystalline, can be spun into synthetic fibers. This polymer is, however, subject to some inherent disabilities which restrict its utility in the fabrication of general purpose fibers. For example, a high-molecular-weight, fiber-forming, crystalline polyolefin such as polypropylene, is a relatively insoluble, chemically inert, hydrophobic material. Since it is not readily permeable to water, it cannot be dyed satisfactorily by the ordinary dyeing procedures. Since it is relatively inert chemically, it cannot be readily dyed even with hydrocarbon soluble dyestuffs. Furthermore, substantially crystalline polypropylene yarns and fibers cannot be dyed readily with a wide variety of dispersed, premetallized and acid-type dyes, nor can such yarns and fibers be dyed to deep shades having good light and gas fastness. Moreover, the susceptibility of polypropylene fibers to oxidative degradation, instability toward ultraviolet light and poor weathering characteristics have further limited their utility. Hence, it is apparent that the development of procedures whereby fibers free from the above-mentioned disabilities may be obtained in order to increase their value in the textile field, represents a highly desirable result.

It is apparent from the foregoing that the problem of obtaining polypropylene fibers having the high tenacity, low elongation and the other desired properties without the accompanying undesirable limitations described above, has presented problems to prior art workers in this field for many years.

Recent advances in improving the dye affinity of polypropylene fibers have been disclosed in co-pending Coover and Joyner applications Serial Nos. 860,648, 6,595, 6,596, 6,597 and 6,598 by Coover, one of our co-workers and by Joyner, one of the co-inventors in the instant invention. Revealed in these aforementioned applications is the blending of certain polymeric materials into crystalline polypropylene for the purpose of obtaining compositions which can be melt spun into high strength fibers and yarns having excellent dye affinity for a variety of dyestuffs. The dyed materials obtained thereby are shown to exhibit very good light and gas fastness. In spite of the obvious advantages derived from the use of these polymeric dyeassisting adjuvants in polypropylene yarns and fibers, the dyed materials obtained therefrom may be subject to the disability of poor dry cleaning fastness. The action of dry cleaning agents such as perchloroethylene is especially severe, and in certain instances it has been found that some of the dye was extracted from the fiber. This problem of the action of dry cleaning solvents is to some extent a limitation of the textile utility of the dyeable polyolefin fibers described in the above-mentioned applications. Fur- 3,246,552 Patented Mar. 15, 1966 ther, there has been disclosed in another companion application Serial No. 637,082 (now U.S. Patent No. 2,984,- 634) by Caldwell and Gilkey, two of the inventors in the instant invention, compositions comprising polyolefins and certain transition metal salts including nickel, cobalt and chromium salts. When these salts are incorporated into unmodified polypropylene in order to improve the dye afiiffinity of yarns and fibers obtained therefrom, relatively high concentrations of the metal salts are required. As a result, the natural or undyed yarns are highly colored. Therefore, in some instances such fibers would not be broadly acceptable to the textile industry even though their dyeability was good.

It has been found now that the properties of crystallizable polymeric hydrocarbons can be improved over a wider area than heretofore accomplishable by the incorporation into the polymer of both a polyvalent transition metal and, in addition, a dyeable polymeric modifier such as is disclosed herein. The presence of the metal in the polymeric hydrocarbon improves the dyeing properties of the polymer, as well as the adherence of printing inks, sizing agents and other coating agents, the polymeric modifier functioning as an internal carrier for the dye. In this manner, relatively low concentrations in the amount of 0.020.2% of metal can be fully utilized even in superhigh-tenacity yarns due to the carrier action of the polymeric modified in transporting the dye to the available mordantingor chelating-metal sites. The metal compound, and the modifier, are dispersed uniformly throughout the cross-section of the extruded or shaped article. Thus, super-high-tenacity yarns and other products can be produced which have practically no color and dye to deep shades. The advantages of a colorless yarn are apparent in that in certain applications there would be no need for a colored or dyed fiber. Equally obvious are the advantages of a super-high-tenacity yarn which can be dyed to deep shades, for example, in the manufacture of carpets. Two of the inventors in the instant application, viz. Caldwell and Gilkey have additionally concurrently filed a companion case, Serial No. 109,829, which is intended to augment the present subject matter consisting of polypropylene, a polyvalent metal compound and an addition polymer, whereby a more specific composition is disclosed possessing a broader coverage particularly utilizing a condensation polymer as the polymeric modifying agent.

Accordingly, it is an object of this invention to provide polypropylene fibers having improved dye affinity. Another object of this invention is to provide substantially crystalline polypropylene yarns and fibers with suitable dyeing characteristics so that they can be dyed readily with a wide variety of dispersed, premetallized, and acidtype dyes which normally will not dye unmodified polypropylene. Another object is to provide partially or completely crystalline polypropylene yarn and fibers which can be dyed to deep shades with excellent light and gas fastness, and which have better resistance to dry cleaning solvents. Another object of this invention is to provide a means for improving the dry cleaning fastness of the dyed yarns and fibers described herein without deleteriously affecting the physical properties thereof, or the melt spinning characteristics of the polymeric compositions from which they were derived. Still another object is to provide polypropylene yarns and fibers having increased resistance to oxidation, and weathering in addition to excellent physical properties. Further objects of our invention will become apparent from an inspection of the following description.

In accordance with this invention it has been found that compounds of certain transition metals, especially nickel and cobalt, may be incorporated into the dyeable compositions somewhat as disclosed in the above referenced Coover and Joyner applications to give yarns and fibers which can be dyed with any dyestuff capable of forming chelates; deep shades having excellent dry cleaning fastness are obtained. It would have been predicted, contrary to what we have described, that the presence of these transition metal salts in effective concentrations might deleteriously affect the color of the undyed yarn. This would have been undesirable from a textile point of view, since it would have made the use of white and light colors difficult. We discovered, however, that low concentrations of transition metals, as nickel and cobalt, could be used to give excellent results provided the salts of the metals were first compounded with a polymeric modifier before incorporation into the polypropylene.

The practice of this invention is directed primarily to the improvement of the physical properties of crystallizable polymeric hydrocarbons. Among the hydrocarbons that can be used to form these polymers are styrene, ethylene, propylene, butylene, 4-rnethyl-l-pentene, allylbenzene and other related mono-olefinic hydrocarbons. The crystalline polymers can be prepared from the monoolefinic hydrocarbons by various procedures, for example, polymerization of an a-mono-olefinic hydrocarbon with a metalcontaining catalyst such as aluminum alkyls, molybdenum, chromium or vanadium oxides or similar metal-containing catalyst with or without an activator such as a titanium compound, sodium compound and the like. The polymeric hydrocarbons can be in the form of a fiber or other extruded or shaped object. Products from these polymeric hydrocarbons can be advantageously formed by any of the melt spinning or extrusion techniques, and the fiber or film produced in this manner can be drafted or crystallized, then dyed or printed readily by any of the known printing and dyeing techniques.

More particularly, however, any fiber, film or other shaped object made from crystallizable hydrocarbon polymers can be modified by the process of this invention to impart improved properties to the polymer. Suitable types of crystallizable hydrocarbon polymers are described by Natta in Makromolecular Chemie, 16, 2l3-237 (1955), and Angew. Chem., 68, 393 (1956).

The preferred transition metals the salts of which are incorporated into the polymeric hydrocarbons in accordance with our invention are nickel and cobalt. Preferably the nickel or cobalt salts (or mixtures thereof) are used in concentrations such that the percent concentration of the metal will be in the range of 0.02 to 0.2 based upon the polypropylene present in the formulation. Metal concentrations in the range of 0.2 to 0.5% can be used, but are less desirable. The metal can be incorporated into the polymeric hydrocarbons in the form of their organic salts, such as the acetates, butyrates, carbonates, pelargonates, benzoates, tartrates, oxalates, salicylates, adipates, etc., and as mixed organic salts such as the hexanoate pelargonate. Chelate compounds of nickel and cobalt may be used, also. For example, the nickel chelate derivatives of the 2,2-thiobisphenols may be used. In particular, the nickel chelate of 2,2'-thiobis(4-t-octylphenol) could be used. Inorganic salts of cobalt and nickel, such as the sulfates, fluosilicates, phosphates, fluorides, hydroxides (or oxides), etc., may be used. The inorganic salts are somewhat less desirable, because it is often necessary to subject these salts to extensive ballmilling to reduce them to a satisfactory partical size.

In the preferred embodiment of our invention, the transition metal compound or metal salt, such as a carboxylic acid salt of the metal, is incorporated into the polymeric modifier by rolling the salt and modifier on the rolls of a rubber mill or by blending in a Banbury mixer. Any of the usual blending procedures, however, could be employed for this purpose. The resulting salt-containing modifier is then incorporated into the polypropylene as described in the referenced Coover and Joyner applications, that is, by mechanical blending followed by melt extrusion thereof. It should be pointed out that precom- 4. pounding of the transition metal salt and the polymeric modifier is the preferred procedure and aifords optimum results, but other less desirable ways may be followed as will be described. The extruded fibers, films, or other shaped objects so obtained can be readily dyed by any of the conventional procedures.

Alternate, but less preferred, embodiments of our invention include the rolling or otherwise compounding the metal compound or metal salt with the polypropylene, thence blending the same with the modifier, and extruding or shaping into the final product. Additionally, the modifier and polypropylene may be compounded, and then blended with the metal compound or metal salt prior to extrusion or processing. A still further embodiment would include the simultaneous blending of all three components, and extruding or shaping. In some instances the metal component can be incorporated during polymerization.

In another embodiment of this invention the transition metal compound can be incorporated into the modified crystallizable polymeric hydrocarbon prior to the spinning, extruding or otherwise shaping of the polymeric hydrocarbon. In this embodiment of the invention, the metal compound is dispersed uniformly throughout the cross-section of the modified film, filament or other shaped object of the polymeric hydrocarbon. Several other methods can be employed to obtain an intimate dispersion or solution of the metal compound in the polymeric hydrocarbon. One method of obtaining such an intimate dispersion involves slurrying powdered polymeric hydrocarbon in a liquid dispersion or solution of the compound of the transition metal. The slurry is then evaporated to dryness leaving the metal compound attached to or coating the particles of the polymeric hydrocarbon. The resulting powder is then blended with the modifier and extruded into fibers or films which consist of a uniform dispersion or solution of the metal compound and modifier in the crystallizable hydrocarbon polymer. Carboxylic acid salts of the transition metals containing 6 or more carbon atoms are compatible with the polymeric hydrocarbon and consequently lead to a solution of the transition metal compound in the polymeric hydrocarbon.

Another procedure for incorporating the metal compound in the polymeric hydrocarbon involves milling the metal compound with the polymeric hydrocarbon on heated rolls. The polyvalent metal compound is added as a solution or dispersion or in a powdered form to the polymeric hydrocarbon as it is being milled on the heated rolls and while the polymeric hydrocarbon is in a semimolten condition. The polymer dispersion or solution can then be blended with the modifier and extruded into fibers or films which can be readily dyed by any of the well known procedures.

Another method for incorporating the polyvalent metal compound into the polymeric hydrocarbon involves dissolving or suspending the compound of the polyvalent metal in a solution of the polymeric hydrocarbon. The polyvalent metal compound is suspended in an organic liquid which is a nonsolvent for the polymeric hydrocarbon at low temperatures but which readily dissolves the polymeric hydrocarbon when heated. The polymer is dissolved in the hot suspension containing the polyvalent metal compound and the mixture is then allowed to cool. The polymer crystallizes out of the solvent carrying with it the polyvalent metal compound as a fine dispersion in the polymeric hydrocarbon. The polymer is then filtered and dried and the dried polymer can be blended with the modifier and extruded into fibers or films which can be drafted, crystallized and dyed or printed by any of the known procedures.

Still a further embodiment of our invention would be to dissolve or disperse the metal compound and modifier together in a liquid medium, and the solution or suspension slurried onto the polypropylene prior to extrusion.

The metal compounds that are incorporated into crystallizable polymeric hydrocarbons in accordance with this invention can be deposited on a finely-divided support. The metal compounds can be used alone in practicing the invention, but good results can also be obtained when the metal compounds are deposited on a fine support that has an active surface or a porous structure prior to addition and incorporation in the polymeric hydrocarbon. The support tends to increase the exposed area of the metal compound and, in general the support should have a particle size less than about 3 microns and preferably less than about 0.5 micron. Suitable supports that can be used are silica gel, activated alumina, ultrafine calcium carbonate, magnesium carbonate, magnesium oxide, calcium silicate and magnesium silicate.

Preferred cob-alt compounds are cobaltous acetate tetrahydrate, cobalt sulfate, cobalt pelargonate, cobalt tartrate, and cobalt Z-ethylhexanoate. Preferred nickel compounds are nickel pelargonate, nickel stearate, nickel adipate, the nickel chelate derivative of 2,2'-thiobis(4-toctylphenol), nickel acetate, and nickel phosphate. Also, chromic acetate may be used. The variety of polymer and copolymer modifiers which may be used Will be described in detail hereinafter. The polymeric modifiers preferably employed are addition type polymers such as poly(vinylbutyral). poly(methyl methacrylate), and the like. In accordance with our invention it has been found that polymeric blends of polypropylene and an effective concentration of about 1 to about 25% and more preferably about 5 to about 15%, by weight based on the blend, of one or more of such addition polymers in combination with the aforementioned transition metals, can be spun into high strength fibers and yarns having the same percentage composition.

As apparent from the preceding description we have found that certain polymeric blends of crystalline polypropylene in combination with, for example, only very minor amounts of transition metal compounds and with the aforementioned addition type polymer modifiers can be spun into high strength fibers and yarns having excellent affinity for dispersed and chelatable dyes as well as excellent light and gas f-astness. This was quite surprising since it could not have been predicted from the prior art. According to the prior art, poly(methylrnethacrylate), when used as a modifier for acrylic fibers, such as acrylonitrile fibers, imparts only a low affinity for dispersed dyes and, even so, the dyed materials obtained thereby exhibit very poor light fastness. Further the incorporation of polyvalent metal compounds into crystalline polypropylene has required relatively high concentrations thereof for obtaining the desired dye properties, and some coloring of the yarn due to the metal was experienced.

Although unmodified polypropylene shows virtually no affinity for dyestuffs, it can be dyed with some dyes to weak shades having, however, very poor fastness properties as mentioned hereinbefore. Surprisingly, it has been found that the shades produced by a given dye on the unmodified polypropylene yarn and on the modifiers themselves were quite different from the shades produced by the same dye on the modified polypropylene yarns of this invention. This unpredictable result indicates that the fibers spun from the polymeric blends described above possess characteristics which ordinarily would not have been expected in fibers spun from simple mixtures of polymeric materials. In this connection, it was also discovered that the modified polypropylene fibers described herein were several times more resistant to oxidative degradation than fibers obtained from unmodified polypropylene.

The modified polypropylene fibers of this invention are also more stable toward ultraviolet light and weathering conditions than unmodified polypropylene fibers. These modified polypropylene fibers and yarns may be further stabilized against thermal breakdown and Weathering with any of the conventional stabilizers for polyolefins. It is usually convenient to add such stabilizers to the polymeric blends before spinning into fibers.

The modified polypropylene fibers and yarns of this invention may be drawn to give the same high tenacities, low elongations and other excellent properties found in unmodified polypropylene fibers and yarn. This is quite surprising, since the addition type polymers used as modifiers, such as the acrylic and methacrylic esters, are substantially noncrystalline when prepared by conventional methods and, as a result, give fibers which possess low tenacities and high shrinkage properties. It would have been predicted, contrary to our discovery, that these materials, when used to modify polypropylene for fibers and yarn, might have deleteriously affected the properties of the yarn.

Another unusual feature of this invention is the fact ,that the polymeric acrylic and methacrylic esters and other addition type polymers used to modify polypropylene could not be used satisfactorily to modify polyolefin fibers in general. For example, when these modifiers were incorporated into high density or into conventional polyethylene, they were found to be substantially incompatible. Thus, a blend of polyethylene parts) and poly-methylmethacrylate) (10 parts) on melt spinning gave fibers which were badly segmented. When these fibers were drafted, fibrillation resulted, giving a substantially useless product in contrast to the polypropylene fibers of our invention which showed no fibrillation when rafted.

According to the practice of the invention, the monomers which are suitable for polymerization into the useful polymeric compositions for blending with polypropylene in accordance with this invention are those represented by the generic formula:

wherein R is hydrogen or methyl and R is an alkyl, alkoxyalkyl, cycloalkyl, aralkyl or aryl radical desirably containing 1 to 12 carbon atoms.

The monomeric units which are described herein can be present either in the form of a homopolymer or in the form of a copolymer of the desired acetal, methacrylate, or vinyl pyridine with another monomer or with styrene, a N-substituted acrylamide, vinyl acetate, or ethyl fumarate as hereinafter defined.

Useful copolymers then, can be composed of two or more different acetal, methacrylate, or vinyl pyridine units, as set forth hereinbefore, or of these materials and one or more vinyl pyridine or N-substituted acrylamide units, as hereinafter described. Monomeric units of the latter type are those derived from (1) vinyl pyridines having the formula:

wherein R is hydrogen or methyl, R is a lower alkyl group desirable containing 1 to 4 carbon atoms, n is an integer from 0 to 4, and (2) N-substituted acrylamides having the formula:

t CHz=C-CNR R wherein R is hydrogen or a lower alkyl group desirably containing 1 to 4 carbon atoms; R is hydrogen or an alkyl, cycloalkyl, aralkyl, or aryl group desirably containing 1 to 18 carbon atoms and R is an alkyl cycloalkyl, aralkyl or aryl group desirably containing 1 to 18 carbon atoms. Suitable monomers include 2-vinyl pyridine, 3-vinyl pyridine, 4-vinylpyridine, S-ethyl-Z-vinyl pyridine,

2-methyl-5-vinyl pyridine, 2-methyl-6-vinyl pyridine, 2,4- dimethyl-6-vinyl pyridine, -propyl-2-vinyl pyridine, 5-isobutyl-2-vinyl pyridine, 2-isopropenyl pyridine, N-isopropylacrylamide, N-isopropylmethacrylamide, N,Ndimethylacrylamide, N-phenylacrylamide, N-cyclohexyL acrylamide, N-butylacrylamide, N,N-diethylacrylamide, N-ethylacrylamide, N-methylacrylarnide, N-methyl-N- phenylacrylamide, and N-dodecylacrylamide.

Hence, the polymeric modifiers of this invention may also be described as polymers containing recurring units having the general structure:

wherein R and R are as defined above, Z is the residue of an unsaturated, polymerizable vinyl pyridine or N-substituted acrylamide, as described above, and x and y are integers which will provide a homoor copolymer having a molecular weight of at least 1000. It is obvious that the nature of the unsaturated, polymerizable vinyl pyridine or N-substituted acrylamide units are subject to wide variation. The truly important feature of the modifier is that acrylate or methacrylate units of the type described above be present therein, preferably in amounts of from 50 to 100 mole percent.

Those radicals which can be present in the ester group of the monomeric acrylate or methacrylate, as described by R in the above formulas, are subject to wide variation and include, for example: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, Z-ethylhexyl, nonyl, lauryl, dodecyl, cyclopentyl, cycloheptyl, cyclohexyl, trimethylcyclohexyl, benzyl, phenylhexyl, phenyl, trimethylphenyl, diphenyl, methoxyethyl, ethoxybutyl, methoxylauryl and ethoxyethyl.

The monomeric units described above may comprise less than 50 mole percent, e.g., 40, 30, 20, or even 10 mole percent of the polymeric modifier, but mole percentages of 50 to 100 percent are preferred particularly where good dye affinity for dispersed dyes is desired.

It has been found that blends of crystalline polypropylene with the polymeric modifiers described can be melt spun into high strength yarns which can be dyed to deep, light and gas-fast shades by means of dispersed and premetallized dyes. The dyeing process can be carried out using conventional procedures either with or without carriers. The polypropylene blends can contain from 1% or less to 25% or more, by Weight of the homoor copolymeric modifier, although the preferred concentration of modifier is from 5 to However, there are special situations which may warrant the use of 30 or perhaps even 40% by weight based on the blend, of certain of the polymeric modifiers disclosed. Furthermore, even though as little as 1% by weight based on the blend, of the specified polymeric modifiers will impart dye affinity to the fibers, it is preferred that amounts of at least 5% be employed, particularly Where deep shades are desired. Polypropylene blends of this type can be melt spun at temperatures ranging from to 65 C. lower than are necessary to melt spin pure polypropylene.

Some specific polymeric modifiers useful in the practice of this invention are:

Poly (methyl methacrylate) Poly(ethyln1ethacrylate) Poly(isopr0pyl methacrylate) Poly(n-propyl methacrylate) Poly(n-butyl methacrylate) Poly(isobutyl methacrylate) Poly (tert-butyl methacrylate) Poly(n-hexyl methacrylate) Poly(lauryl methacrylate) Poly(cyclohexyl methacrylate) Poly(benzyl methacrylate) Poly(phenyl methacrylate) Poly(methyl acrylate) Poly(n-propyl acrylate) Poly(n-butyl acrylate) Poly (Z-rnethoxyethyl acrylate) Poly( 2-ethoxyethyl acrylate) Poly(2-ethylhexyl acrylate) Po1y(vinyl acetal) Poly(vinylbutyral) Poly(Z-methyl-5-vinylpyridine) 75/25 copolymer methyl acrylate/ ethyl methacrylate 20/80 copolymer ethyl acrylate/N-tert-butylacrylamide 25/75 copolymer methyl methacrylate/N,N-dirnethylacrylamide 50/50 copolymer methyl methacrylate/2-methyl-5-vinyl pyridine 75/25 copolymer ethyl acrylate/2-methyl-6-vinyl pyridine 50/50 copolymer 2-vinyl pyridine/ethyl acrylate 50/50 copolymer methyl methacrylate/3-isopropenyl pyridine 60/ 30/ 10 terpolymer N ,N-dimethylacrylamide/N-isopropyl acrylamide/ methyl methacrylate 98/2 copolymer methyl methacrylate/ ethyl furnarate 20 copolymer methyl methacrylate/vinyl acetate 50/ 50 copolymer methyl methacrylate/styrene 75/25 copolymer N,N-dimethylacrylamide/methyl methacrylate 80/20 copolymer N-methylmethacrylamide/ styrene Nora-The integers given to indicate the copolymer composition are based on mole percent here and throughout the specification.

It is to note that any polymeric modifier having a molecular weight in excess of 1000 which is capable of inrtoducing the specified percent by Weight, based on polypropylene, or the described monomeric units into the blend is within the scope of our invention.

Suitable dyes that can be employed in dyeing any of the hydrocarbon polymers described herein include those set forth in the annual edition of the Technical Manual and Yearbook of the American Association of Textile Chemists and Colorists, for example, the 1952 edition. Among such suitable dyes are those illustrated by the a-hydroxyanthraquinone compounds and by the orthohydroxyazo compounds, which are capable of undergoing chelation or mordanting with the metals or metal compounds which are incorporated into our hydrocarbon polymers. Thus among the dyes that can be used are those described in US. Patents 2,641,602 and 2,651,641. These dyes have the structural formulas:

and

respectively, wherein Q represents a phenyl ethyl alcohol nucleus and A is a monocyclic benzene nucleus containing a (']HOH group wherein R represents hydrogen, methyl or ethyl. Other dyes which can be used to color the crystallizablc polymeric hydrocarbons within the scope of this invention are:

2- (4-acetamidophenylazo) -4-methylphenol 4-hydroxy-1-methyl-3 m-nitrophenylazo -carbostyril 1-amino-4,5-dihydroxy-2'methoxyanthraquinone 1-(Z-hydroxy-S-sulfonamidophenylazo)-2-hydroxynaphthalene The above dyes are merely representative of dyes that can be used.

When premetallizcd dyes (dyestuffs chelated with the metal prior to use) are employed to dye the modified polypropylene yarns and fibers of the reference Coover and Joyner applications, they do not give shades which are fast to dry cleaning solvents such as perchloroethylene. When the preferred metals of this invention, however, are compounded into the modified yarns and fibers as described herein, shades having excellent dry cleaning fastness are obtained when these yarns and fibers are contacted with the nnmetallized dyes.

Usually, it is preferable to prepare the modified polypropylene compositions from polypropylene having a conditioned density above 0.900 and an inherent viscosity in tetralin at 145 C. of from 0.9 to 1.2. Conditioned density, as used herein, refers to the density determined on a sample which has been annealed in an attempt to obtain maximum crystallinity. A conventional annealing procedure involves placing the sample in a tube, heating under high vacuum or in a nitrogen atmosphere to just below the softening point, and allowing the sample to cool slowly. Polypropylene having inherent viscosities above 1.2 can be used in preparing the modified compositions, but then it is usually necessary to degrade these compositions thermally to a lower viscosity in order to realize optimum melt spinning characteristics and fiber properties. The temperatures required for this degradation are usually above 300 C. and often result in an appreciable loss of modifier through depolymerization or degradation. Polypropylene of inherent viscosity less than 0.9 can be used in preparing modified compositions for melt spinning, but does not afford fibers having optimum physical properties. Furthermore, these modified polypropylene compositions can be formed into the various cross-sections, e.g., cloverleaf, Y-section, etc., by employing spinnerettes or dyes having appropriately shaped orifices.

The following examples are introduced to illustrate but not necessarily to limit our invention.

Example 1 A mixture of 65 parts of poly(vinylbutyral) and 1 part of cobaltous acetate tetrahydrate were compounded on the rolls of a rubber mill. The resulting slab of cobaltcontaining polymer was granulated and was used as described hereinafter.

Blends of crystalline polypropylene (I.V.=1.08 in tetralin at 145 C.) with the cobalt-containing poly(vinylbutyral) from above were prepared by melt extrusion of the mechanical mixtures of the two resins. These blends were melt spun into SO-filament yarns having the properties shown hereinafter.

with dyes capable of forming chelates with transition metals. Deep shades which were both lightand gas-fast were easily obtained. When the dyed yarns were sub- 10 jected to the action of perchloroethylene at 100 F. for 4 hours in an accelerated dry cleaning (A.D.C.) test, the shades were found to be substantially unaifected. Some of the specific dyes employed were 2-(4-acetamidophenylazo -4-methylphenol and 4-hydroxy-1-methyl-3- (m-nitrophenylazo -carbostyril.

Example 2 I II III Polypropylene, percent 90 88 85 Poly(methyl methacrylate), percent 10 12 15 Nickel, percent as the metal based on polypropylene. 0. 2 0. 1 0. 08 Yarn viscosity 0. 91 0.82 0. 79 Total denier r 168 127 111 Tenacity, g./den 7.06 5. 83 6.11 Elongation, percent 21 2O 19 Elastic modulus, g./den 52 52 47 Knit tubes prepared from these yarns all dyed to deep shades having excellent resistance to dry cleaning solvents such as perchloroethylene. Some of the dyestuffs which were employed were 2-(4-acetamidophenylazo)-4-methylphenol, 1- 4-hydroxyethylanilino -4,5-dihydroxy-8-nitroanthraqninone, and 4-hydroxy-1-methyl-3-(m-nitrophenylazo)-carbostyril. In general, the dyestuffs having the o-hydroxyazo or o,o'-dihydroxyazo structure were especially valuable in this connection.

Similar results were obtained when either nickel stearate, nickel hexanoate pelargonate, or cobalt sulfate was used in place of the nickel pelargonate.

Similar results were obtained, also, when the .poly- (methyl methacrylate) was replaced by a 98/2 copolymer methyl methacrylate/ethyl fumarate or poly(nbutyl methacrylate).

Example 3 Blends of crystalline polypropylene with an /20 copolymer methyl methacrylate/vinyl acetate and cobalt pelargonate were prepared. The cobalt pelargonate and the copolymeric modifier were first compounded by rolling on the rolls of a rubber mill. The resulting composition was granulated and was then mechanically blended with the pellets of polypropylene. The mechanical blends so produced were melt extruded followed by repelleting of the resulting formulations. These modified polypropylene formulations were then melt spun into SO-filament yarns having the properties shown below. Knit tubes fashioned from these yarns were readily dyed with orthohydroxyazo compounds and ot-hydroxyanthraquinone derivatives. Deep shades which were fast to dry cleaning solvents were easily obtained.

I II I III Polypropylene, percent 92 87 80 80/20 Copolymer MMA/VA, percent 8 13 20 Cobalt, percent as the metal based on polypropylcne. 0.01 0.03 0.3 Yarn vlscosity 0. 84 0. 76 Total denier r 139 65 103 Tenacity, g./den 6.00 5. 60 5.01 Elongation, percent. 21 18 15 Elastic modulus, g./den 55 55 64 Similar results were obtained when the cobalt pelar-' gonate was replaced with either cobalt tartrate, nickel adipate, or the nickel chelate derivatives of 2,2'-thiobis (4-t-octylphenol) Excellent results were obtained when the 80/20 copolymer methyl methacrylate/vinyl acetate was replaced with a 50/50 copolymer methyl methacrylate/styrene or a 75/25 copolymer N,N dimethylacrylamide/methyl methacrylate.

Example 4 The procedure of Example 3 was followed using poly (Z-methyl-S-vinylpyridine) as the modifier and nickel acetate as the transition metal salt. The resulting yarns had tenacities ranging from 4.3 to 7.1 g./ den. Knit tubes of these yarns dyed to deep shades with orthohydroxyazo compounds and ahydroxyanthraquinone derivatives. The dyed yarns when subjected to the ADC. test with perchloroethylene showed little or no tendency to fade.

Example The procedure of Example 1 was followed using an 80/20 copolymer Nmethylmethacrylamide/styrene as the modifier and cobalt 2-ethylhexanoate a sthe transition metal salt. The yarns obtained showedtenacities ranging from 4 to 8 g./den. and could be dyed with orthohydroxyazo compounds to deep shades which showed no tendency to fade when subjected to the action of perchloroethylene in the ADC. test.

Equally good results were obtained when chromic acetate was used in place of the cobalt 2-ethylhexanoate.

Example 6 The procedure of Example 1 was followed using poly (vinylacetal) as the modifier and nickel phosphate as the transition metal salt. The latter was subjected to the action of a ball mill for 4 days prior to using in order to obtain a very fine particle size. The yarns obtained were readily dyed to deep shades with excellent dry-cleaning fastness.

Thus, by means of this invention, substantially crystalline polypropylene yarns and fibers having improved dye afiinity, excellent light and gas fastness and increased stability may be obtained. The improved polypropylene fibers of this invention may be used in the same manner as conventional polypropylene fibers; for example, they can be woven into wool-like blankets or used in the production of automobile seat covers and marine hawsers that are as strong as nylon and much cheaper.

The invention has been described in considerable detail with particular reference to certain preferred embodiinents thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinbefore and as defined in the appended claims.

We claim:

1. As a composition of matter, a shaped crystalline polymerized a monoolefinic hydrocarbon having improved dyeability containing 1 to 25% by weight of a polymer selected from the group consisting of polyvinylacetal, polyvinylbutyral and addition polymers containing recurring alkyl acrylate units based on the weight of polymers present and a carboxylic acid salt of a metal selected from the group of nickel, cobalt and chromium in an amount which provides a metal content of from 0.02 to 0.5% by weight of the hydrocarbon polymer present.

2. A composition of claim 1 wherein the amount of addition polymer present is 5 to 15% by weight of the polymers present.

3. A composition of claim 1 wherein the metal compound present is in the form of a salt of nickel.

4. A composition of claim 1 wherein the metal compound present is in the form of a salt of cobalt.

5. A composition of claim 1 wherein the shaped crystalline polymerized ot-monoolefinic hydrocarbon is polypropylene.

6. A composition of claim 2 wherein the shaped crystalline polymerized a-monoolefinic hydrocarbon is polypropylene.

7. A composition of claim 1 wherein the addition poly mer is poly(methyl methacrylate).

8. A composition of claim 6 wherein the addition polymer is poly(methyl methacrylate).

9. Dyed fibers having the composition set forth in claim 1.

10. Dyed fibers having the composition set forth in claim 2.

11. A composition of claim 1 dyed with a chelatable dye.

12. The process of obtaining dyed fibers which comprises dyeing fibers having the composition set forth in claim 1 with a dye which chelates with the metal present in the fibers.

13. A composition of claim 1 wherein the addition polymer contains recurring alkyl acrylate units.

14. A composition of claim 1 wherein the polymer is polyvinylbutyral.

References Cited by the Examiner UNITED STATES PATENTS 2,571,683 10/1951 Coover et a1. 26045.5 2,628,214 2/1953 Pinkney et al. 26045.5 2,882,263 4/1959 Natta et al. 26093.7 2,927,904 3/1960 Cooper 26045.50 2,984,634 5/1961 Caldwell et al 26030.8 3,003,845 10/ 1961 Ehlers 26045.5 3,153,680 10/1964 Giustiniani et al. 260897 3,156,743 11/1964 Coover et a1 260897 FOREIGN PATENTS 557,717 11/1957 Belgium. 1,198,579 12/1959 France.-

WILLIAM H. SHORT, Primary Examiner.

DANIEL ARNOLD, Examiner. 

1. AS A COMPOSITION OF MATTER, A SHAPED CRYSTALLINE POLYMERIZED A - MONOOLEFINIC HYDROCARBON HAVING IMPROVED DYEABILITY CONTAINING 1 TO 25% BY WEIGHT OF A POLYMER SELECTED FROM THE GROUP CONSISTING OF POLYVINYLACETAL, POLYVINYLBUTYRAL AND ADDITION POLYMERS CONTAINING RECURRING ALKYL ACRYLATE UNITS BASED ON THE WEIGHT OF POLYMERS PRESENT AND A CARBOXYLIC ACID SALT OF A METAL SELECTED FROM THE GROUP OF NICKEL, COBALT AND CHROMIUM IN AN AMOUNT WHICH PROVIDES A METAL CONTENT OF FROM 0.02 TO 0.5% BY WEIGHT OF THE HYDROCARBON POLYMER PRESENT.
 9. DYED FIBERS HAVING THE COMPOSITION SET FORTH IN CLAIM
 1. 